<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>

    div {
      width: 180px;
      height: 100px;
      background-color: #f00;

      border: 10px solid green;
    }

    .box {
      /* 设置圆角 */
      /* 设置具体的数值 */
      /* border-radius: 20px; */
      /* 设置百分比 */
      /* 百分比相对于谁, 了解即可 */
      border-radius: 10%;
    }

    .content {
      border-radius: 20px;
    }

    .home {
      width: 100px;
      height: 100px;
      border: 10px solid red;
      background-color: #0f0;

      border-radius: 50%;
    }
  </style>
</head>
<body>
  
  <div class="box"></div>
  <div class="content"></div>


  <div class="home"></div>

</body>
</html>